This proposed study is to learn more about immune mechanisms which may contribute to the pathogenesis of inflammatory periodontal disease. Humans will be skin tested for hypersensitivity to several oral microorganisms to see if correlations occur with severity of periodontal disease. Subgingival and supragingival smears will be examined by immunofluorescence for in vivo coating of bacteria by IgE, IgA, IgM, IgG, C3 and C4. The specificity of antibodies in gingivae will be studied by a double labeling immunofluorescence test.